Contrasting photosynthetic characteristics of forest vs. savanna species (Far North Queensland, Australia)
File(s)
Published version
Author(s)
Type
Journal Article
Abstract
Forest and savanna are the two dominant vegetation types of the tropical regions with very few tree species common to both. At a broad scale, it has long been recognised that the distributions of these two biomes are principally governed by precipitation and its seasonality, but with soil physical and chemical properties also potentially important. For tree species drawn from a range of forest and savanna sites in tropical Far North Queensland, Australia, we compared leaf traits of photosynthetic capacity, structure and nutrient concentrations. Area-based photosynthetic capacity was higher for the savanna species with a steeper slope to the photosynthesis ↔ nitrogen (N) relationship compared with the forest group. Higher leaf mass per unit leaf area for the savanna trees derived from denser rather than thicker leaves and did not appear to restrict rates of light-saturated photosynthesis when expressed on either an area or mass basis. Median ratios of foliar N to phosphorus (P) were relatively high (>20) at all sites, but we found no evidence for a dominant P limitation of photosynthesis for either forest or savanna trees. A parsimonious mixed-effects model of area-based photosynthetic capacity retained vegetation type and both N and P as explanatory terms. Resulting model-fitted predictions suggested a good fit to the observed data (R2 = 0.82). The model's random component found variation in area-based photosynthetic response to be much greater among species (71% of response variance) than across sites (9%). These results suggest that, on a leaf-area basis, savanna trees of Far North Queensland, Australia, are capable of photosynthetically outperforming forest species at their common boundaries.
Date Issued
2014-12-19
Date Acceptance
2014-11-14
Citation
Biogeosciences, 2014, 11 (24), pp.7331-7347
ISSN
1726-4170
Publisher
Copernicus Publications
Start Page
7331
End Page
7347
Journal / Book Title
Biogeosciences
Volume
11
Issue
24
Identifier
http://gateway.webofknowledge.com/gateway/Gateway.cgi?GWVersion=2&SrcApp=PARTNER_APP&SrcAuth=LinksAMR&KeyUT=WOS:000347959800011&DestLinkType=FullRecord&DestApp=ALL_WOS&UsrCustomerID=1ba7043ffcc86c417c072aa74d649202
Subjects
ADAPTIVE SIGNIFICANCE
BASIN-WIDE VARIATIONS
CLIMATE-CHANGE
EASTERN AUSTRALIA
Ecology
Environmental Sciences & Ecology
Geology
Geosciences, Multidisciplinary
LEAF NITROGEN
Life Sciences & Biomedicine
Physical Sciences
Science & Technology
SHADE TOLERANCE
SOIL PHOSPHATE
TROPICAL RAIN-FORESTS
VEGETATION TYPES
WEST-AFRICA
Publication Status
Published
Date Publish Online
2014-12-19